Think about the chaos of a contested convention, with delegates sprinting around making deals, chased by reporters who will invoke Chicago 1968 at every possible opportunity.

A second ballot would be a “disaster,” Cohen told me. He led the Sanders-backed efforts after the last election to get rid of superdelegates entirely. Leaving them with any kind of role was a compromise, at best a technicality—the idea was that they’d give a numerical boost to whoever already led in pledged delegates. The thought that superdelegates could cost Sanders the nomination is upsetting enough for his supporters. The thought that he could lose to the man who shut down Occupy Wall Street with a dead-of-night police raid and has been nonchalantly spending his way into the Democratic process … it’s just too much.

“The notion that the 750 people who were not elected as delegates are going to come in after the country votes, and 18 months of campaigning and gigantic amounts of volunteer time—it’s really critical for our credibility that we have this first ballot,” Cohen told me, arguing that a contested convention would weaken the party’s ability to beat Trump.